Self-acting resistance for electric motors.



M. KALLMANN, DEGD. I P. KALLMANN, ADMINISTRATRIX. SELF ACTING RESISTANCE FOR ELECTRIC MOTORS.

7 APPLICATION FILED NOV. 16, 1906. I 1,052,961 Patented Feb. 4, 1913.

attorneys 20 motor to be sorted, becomes 1 cooln MAI EJIIN KALLMANN, UF BERLIN, GEEJWQ SELF-.MJTEHG RESIS :EOEL ELECTEEC MCTORS.

Application file November 36,

or?! whom it may concern:

it known that llliiR'ilN Killer/nuns, a citizen. of the l'ili'npire oi. Germany rcsiding at Berlin, in the Kingdom of Prussia o and Empire of Germany, have invented certain no and useful Improvements in SelfilCflllfflTiU-llStfafiCGS for Electric lilotors; and l do hereby declare the following be a full. clear, and exact descriction of the in- :c vention. Slifitll will enable others skilled in the art. to which it appertains to make and use the same.

This invention relates to selfz-tcting starting-resistances for electric motors made of 1-5 conductors of very high positive temperature-cocilicients, preferably of iron, and possessing; the.-proj' erty that the iron or other Leo-celled vsr1slim-resistance. at its first insertion he'fore the armature oi the very highly heated, e itnally up to inco descence and there increases its resistin value very considerably (evenhp to ten times} above that of the cold iron resistance. With increasing e-rmaturespeed the tension clsoroed bv the veriMien-resistance sinks subsequently in consequence of the resistance and decreases, until it finally is, as a. rule, cnt. out in 2 steps by short-circuiling.

Us in the following will be described special forms of construction of sncn. seli act-ing variation startn resistances, the object of which to attain quiet and steady work ing of such se 'l-siarters on starting the nio- .5 tors, as well lhe greatest possible simplicity combined with the smallest cost.

Figures l-7 show dingronnnatic-ally the arrangement of these self-starters while Figs. 8-43 illustrate graphically the work- 0 ing of the variation resistances during the starting-period.

Similar numerals refer to similar parts throughout the several views.

"it. has been found that it is possible to 45 regulate theduration of the starting-period a s well the strength of the rushes ct current which occur at the first switching on and the subsequent switching oil or cut-ting out of the steps of the resistance by a cor- *o responding division the variarionrrcsistanccs into a sullicientl great number of parallel conductors of a very small heat capacity, as well as by series-connection the-variationresistances with a constant re- & sistance, and also by a connection in peri fu ther d fcpecification of 'Lctters Botanic. y; l-myl gfl 115 I}, 1913,,

Sierial Ho. 343,?63.

sistances). For in this way the the starting; of the motor is varied, the vcriators, according to their more or great heat-capacity; are more or less rigidly heated and cooled, on this pends the strength of therush or nrrent "felt at the switching on and switching oil in the net and on the motor. and by c combination ofa connection in series or in parallel (or also by both at the some time) of the veriators wito accurelcly made ccnsiant resistances, it is possible to simplify the construction of the self-regulating start in presist ances within toe limits of the rushes of current allowed respective works, and thus save eX- I peoses, also the load capacity may he incr scd.

1 i a diagrammaiic View of the having similar variation resistances cconcf d in series and with means to automatically cut out the resistances in sections. Fig. 2 is a. (liagrauuna ic view of a starter embodying variators of dili'ercnc resistances connected in multiple and with automatic means for cutting out the variation resistances in sections. Fig; 3 is a diagrammatic view a starter employing variation resistances cminectcd in series, and meansfor manually cutting out the variation resistances in sections. Fig. is a diagrammatic view of a starter comprising the features of the invention in simplified embodiment. Fig. 5 is a diagrsmnuztic view 01" a starter embodying grouped variation resistances and with a solenoid relay adapted to raise and make contact, cutting out a portion of the variation resistance groups and to raise still further and cutout the remaining groups. Fig. 6 shows in diagram a starter cnn'iloying but two variation resistances and with means to retard the act-ion of the automatic cutout. Fig. 7 is a diagrammatic view of manually operated starter having variation resistances connected in series with individual constant resistances connected in parallel one with each variation resistance and cut out therewith, Fig. 8 s

diagram wherein the line .ilh ytretes I the passage of a current at the start while the lower line illustrates the effect of a reducing resistance in circuit. Fig. 10 is a diagram illustrating the rise and fall of current as the variation resistances are cut out in section. Fig. 11 is a diagram similar to Fig. -10 illustrating a smaller load and consequent shorter starting period. Fig.12 is a diagram showing in dotted curve the tension absorbed by the motor under normal conditions, the full line representing the resultant curve of absorption by the variation resistance. Fig. 13 is a diagram showing the variation of resistance in the variators during starting, the full line representinga heavy load on the motor, the dotted line a light load.

In Figs. 15 the variation-resistances are represented in their subdivision into numerous parallel-groups, while in Figs. 35 there have also been added constant series resistances. Figs. 6 and 7 show arrangements without any sub-division of the variationresistance's .into pa 'allel and series connections, but on the other hand in series or in parallel connected resistances.

In F ig. 1 have been switched on in front of the armature 1 of the motor (the magnet-fielcl of the motor has for the sake of simplicity been omitted) bet-Ween thepoints a and 0, several parallel groups of variation-resistances 2, 3 10. The variators consist, as a rule, of very thin iron wires of a thickness of from about up to of a millimeter, which are hermetically inclosed in glass boxes filled with hydrogen, and are during, the starting temporarily 'heated, eventually up to incandescence. An electromagneiic relay 11 provided with two armatures 12 and 16, is for instance connected across the motor armature, so that with the increasing speed of the motor its excitation increases until '(for instance in 220 volts installations) with a counter elect-romotive force of about 150 volts, the small armature 16, on one side, which turns on the axle 17 is attracted against the counter-force of the spring 28 and closes a contact at 19. 'Hereby the part of the variation-resistance lyin between the points a and 6, thus for instance the group of the variators 2 to 7, is shortcireuited' after the same has, after the first heating of all the variators, cooled again in the meantime, For at 150 volts counterpressure all variators together only absorb in the above instance volts and if 3 of the' same are now short -circuited the last third, namely the variator-group 8-40 must for a short time absorb this rest of tension of 70 volts. As aresult the iron resistances are eventually made incandescent again, if the speed of themotor increases suiliciently slowly, or their inertia is small. But then they cool down again, as for instance at a counter electroinot ve force of 200 volts they need only absorb 20 volts. The relay 11 has, as a consequence, been excited to such an extent that the armature 12 is drawn into the coil and effects with the contactarm 13 on the contacts lit and 15 also the switching oil of the last part of the varie tors, by short-circuiting the whole variationresistance. The number of the parallelly connected variators depends on-t'he startingcurrent required for the motor, if for instance at 220 volts there are required 6 amperes for attaining the momentum of starting corresponding with the load on the motor, therefore a. power consumption of GX 220:1.32 kilowatts, 6 series of variators are connected in parallel each of which is calculated for l ampere and thus brings the same to incamlescence at 1 ampere per variator, or 3 series each of 2 amperes a re used when a correspondingly stronger iron wire is used in the single variatiors, which only becomes incandescent at 2 amperes, or else numerous parallel and still thinner iron wires are used in each of the glass boxes. In this way the parallel series are grouped according to the consumption of current and the starting-thin: will be the shorter the thinner the ironwires. are, as the same can then get heated and cool down within a small fraction of a second, as they have a very small heat-capacity. But on the other 5 hand the arrangement is made hereby more l complicated and expensive. The thinner the iron wires are, or the smaller their heat I capacity is, the n'io-re rapidly take place the fluctuations of current at the first switching on of the whole variation-resistance with the motors and at the switching oil of the first part and the last part of the variator groups. so that with a very great subdivision the rushes of current are no longer noticeable and likewise no shocks on the motor.

Fig. 2 shows a similar arrangement as the above described with conductors oi, a small. heat-capacity connected in parallel, in which however, as a variation, instead of, for in stance, three variators of the same size connected in series. only a large and a small one are connected in series, each of which is again divided into pa 'allel sections. In this way the division, for instance into and l of the tension can be made in a. more simple way. The relay 10 shows in Fig. 2 one armature, but which has 2 motion steps. It is again connected with the motor 1, between (land 0 is the above described variation-resistance 2. S) and the armature 11 of (therelay 10 is connected with the point 7) of the variation-resist-ance. It the counter ele'etromotive force has for instance in 220 volt motors reached 150 VOltSythe iron core 11 is,drawn into 10 and shut-circuits in the first place at 13 and 11 the greater part a, 7) of the variation-resistanee,that is to say, the large variators 2---5, and at an increasmos-oer ing tension the contacts 13 and. 14 with the guide-rod 15 are raised by the iron core 3, l

which has been attracted, g'bcr up. unti tho contact arni iii oi. the ii iii armature ll. touches the contacts it) and i7 and disconnects by shortrircuitinn the whole or the rest of the urietioirresistencc. The mode of working? in other respects as illustrated by Fig. l, the varietors of a larger size 2--3 shown as samples are in parallel connection preferably arranged for the same strength of current as the variators of a smaller size 6-4). The number of the rsristors connected in l'JtlIflllPl and the thickness of the iron wires for the same depends, :is already remarked, on the heat-capacity desired, the admissible starting duration, the load and the admissible strength of the shoe ts of current,

In Fig. i there is connected witl the variators 2, 3 7 switched in parallel a constant resistance 9, for instance of nickelin. Behind the same is the armature i of the motor, whose shunt field is marked with 8. For the sake of distinctness the switching of? of the steps is shown as being done by means of a crank, but it can also he eii'ected quite automatically, for instance by the shove described relays. On putting the crank 1.0 on the first contactthe motor is started, While the reducing-resistance 9 end the groups of variators 2-7 (in series parallel) and the armature 1 are connected in series. If the speed of the armature has increased to such an extent that the variators have cooled down suflicientiy (for instance if only volts are absorbed by the re (inning and variation-resistance) the crank is put on the second contact and thereby the constantreducing resistance 9 is switched cit, the variators 2 to 7 receive for a short time the rest of the tension and be come heated, at the further increase of the speed they cool down again, the crank is put on the next contact and 2, 3, 5, 6 switched cit, the rest of the tension is absorbed now by e and 7, which become heated again, and if they have cooled down again, which will be the case at a tension of the armature of about 200 volts, the crank is put on the last contact and the startingpcriod terminated thereby. The field takes current through the resistances.

lnthe construction shown. in 4: resistances 2 to 7 and resistance 8 are at first connected with the armature. Upon. mow ing arm 9 to contact 13, resistances 5 to 7 are short circuited and resistance 8 1 eliminated or cut out, and upon a fur-the movement of arm 9 to contact M resistances 2, 3, and 4t are short circuited. this arrangement is represented in combination with an automatic relay, switched es, for itrtance in 2 steps. Also here are used, as shown by the parallel switching,

Veriators or" a small heat-capacity 2, 3, i 10 connected in front oi the armature 1 of the motor, moreover the constant resistance 12 is connected to this series, in

order to reduce the initial shock of the current, as the vsriators oner otherwise in their first cold state too little resistance. The rehiy 11 is connected to the poles of the armature of the motor; at a corresponding in.- creased speed the iron core 13 with the con tact 15 is raised up to the contact-piece 16, antl as 13 is connected through the lead 14%. with the point 71 of the variation-resistance there takes place, as 16 is connected through the guide-rod 19, with. the positive pole of the net, and over 12 with the point of the varietors, a short-circuiting of the varietors 2 to 7 and of the reducing-resistancc 12,? y the touching of 15 and 16. There remain only connected 8, 9, 10 which absorb, While becoming heated again, the restof the tension at e further increase in the speed oi the motor the iron core 13 is further raised, together with 15, 16 and 19, until 16 is. in contact with 17 and 18, and as 18 is connected to point 0 of the variators, the fixed resistance 12, as well as the Whole variation-resistance, is switched oil. By using a suitable fixed resistance, for instance of nickelin, it is possible,.even in spite of the use c1 relatively inert iron resistances of a thicker'wire, or the like, as rariators Ito sufiiciently reduce the shock of the current at the switching on and switching off, and the construction may be greatly simplitied by recliicing the number of perellel switched varietors.

In Fig. 6 is only used a single series, for instance of two variators 2 and 3,'the same are connected to the armature l of the motor, moreover the fixed reducing resistance between the points a and 7), is connected. to the ariators and the armature. When the speed of the motor increases, the iron core 6 isettrected by the coil 5, and as through the lead 7 is connected with the point 0 of the Variat-ors, the reducing-resistance 4 and the largest of the varietors, 2, are switched off by the contact 8 on 6 through its touching; the bar 1. Now 8, while becoming heated again, absorbs the rest of the tension, until finally, at the further increase of the electroinotive counterfor e, toe iron armature 6 carrying the bar is further raised. But this raisin is tended to set in the last Fig. (3, can be 3 seconds. In this way there is attained that the switching off of the remaining variation-resistance 8 does not take place too rapidly, in order thatthe same, if it possesses a greater inertia in consequence of a thicker wire and larger size, can, at least for the greater part, cool down again, after having absorbed the rest of the tension, for which, as a rule, about 3 seconds are suificient. In consequence of this also more inert resistances of a greater heat capacity may be used in this step without any danger of too great shocks or rushes of current by such an artificial damping even if it is instep the relay 5 to work in the case of a proportionately low electroinotive counter-force, or speed of the motor, in order to be able to work the automatic/ starter even with a low net tension.

In Fig 7'there is finally shown how the power of the variation-starter can still be further increased by a simple and strong construction for working it by hand, which however, quite similar to the one shown in made automatic by working it with relays. Constant resistances 2, 4 and 6 of nickelin or the like are connected to the variators 3, 5 and 7, each of the former being in parallel with one of the latter and each parallel group being in series respectively between (L and Z), Z) and c, c and (Z. The shunt field 14 ot' the motor 1 is already excited at the first position of the crank 10, on the sliding-piece 11, and. hereby the fixed resistance, for instance the nickelin resist:- ance 8, and the series of the variators 3, 5 and 7 with their parallel resistances 2,. t, and 6 are connected to the armature 1. After the motor has attained a sutiicient speed, and if the crank 10 on the slidingpiece 12, which connected with point 0 of the variators, the fixed resistance 8, together with the two variators 3 and 5 and their parallel resistances 2 and l, are switched olt as soon as the same have sutficiently cooled down, and it, for instance, altogether only '70 volts of S, 3, 5 and 7 with 220 volt-motors are absorbed. I These Volts are now absorbed by the last groin) 7 and 6, in consequence of which 7 becomes hot again and increases its resistance, and after the speed of the motor has further iu creased and in consequence of the cooling of 7 only, say, 15 volts are absorbed, the remaining resistance is short eircuited oil, and the starting-period encls. A remarkable fact in this connection is that though it is true that the elasticity of the Variation-resistance 3, 5, 7 is slightly lessened by this parallel switching of 2, 4, (5, a greater load capacity of the variation-starter is attained, for in stance if the variators are brought to incandescence already at '5 amperes, and can only overcome say 5 amperes 220 volts-:11

' after kilowatt of motor-power on the starting, the parallel switching of a constant resistance 2, 4, 6, which absorbs in the heated state of the variators, in consequence of the current-branching in this state only perhaps amperes, the load-capacity could be increased to a starting power of 7 amperes 220 volt':1.5% kilowatts. variation-capacity of the starter sinks, it is true, by this parallel switching, but the slightly greater shock caused by this, by switching ott the steps, is frequently still admissible. It therefore the greater loading is for the sake of economynot to be etl'ected by increasing the number of the variators then the addition of a constant resist ance oiiers within certain limits a means for a better utilization of the variation starters.

Figs. 848 show the working of the different forms of cimstruction. In Fig. 8 the curve A shows that, for instance, by the use of numerous variators of a The slight heat-capacity the shock of the current about 2 ampercs, while when using fewer but inert variators, according to the curve B, the current sinks much slower and is 0.59 seconds still nearly 5 ainperes. But it is pomible, as Fig. 9 shows, by switching on a constant resistance to sutticiently reduce the initial shock of the current even with variators of a great heat-capacity, so that the fluctuation does no longer disturb the net. The upper curve in Fig. 5) shows the passage of the current during the first seconds without the switching on oi? a reducing resistance; the lower curve shows it with a reducing-resistance switched on.

' Figs. 1043 show how the variation-re sistances act when being switched on to the motor.

Fig, 10 shows n'iagnitude oi' the initial shock oi: tl e current, it no constant resistance is switched on to weaken it; the current." then rises at the beginning over the point, 5, whereas for instance with a fixed reducing resistance the current is reduced down to the point a. The current then sinks gradually, wiile the motor is working with its full power, in about 3 seconds, according to the cooling of the resistance and the increase of the speed of the motor down to the point 0. Here the greater part of the variation-resistance, as well as the constant reducnig-resistance, is

in the dotted curve the ma net 'cated in all curves on the'abscissa the duration in seconds.

Fig. 11 is exactly similar to Fig. 10 with only the diti'erence that the power of the motor is smaller here, that is to say the load. In consequence of this the Whole starting-period is innchshorter and lasts only about 3 seconds; also here point b indicates again the shock of the current, at first without, and point a with the switching on of a constant resistance; 12, (Z, indicates again the shock oftlie current at the first, I: that at the second step of stitching olil, undg the permanence.

In Fig. 12 the voltage at the resistance is shown by a full line'cnrve and the at the motor by a dotted line. The rnnonnt of tension absorbed by the stantingn'esistance for instance at the beginning fully- 220 volts, the same as the tension of the net, it sinks within about 3 seconds to 50 volts, which are absorbed by the constant and the variation-resistance, which has cooled down in the meantime. Then takes place shotcircnitingoi. the first step, and. after s. further 2 seconds, during which the enn'nznt oi? tension absorbed by the rest of the vcnntitts has sunk down to about 15 volts, takes place the full switching oil, so hot then the full tension of for instance 22) volts can act in the m'nmture of the motor. curve of the tension on the arnnituze o'l Ill? inotor represents the countei piecc o; showing the tension of the resin 3 shows the variations (1 the resistance undergone by the \"arieiiou stunting-i'esistance during the starti -)i1l(l{l in the curve a, I), 0, (5, c, f, 7, drawn in 'lull liner-t, at the full working oi? the motoi. therciore with a great strain on th 14 vsist'ance, and the dotted curve M, y, z, w v

shows the same with a slight lmlfl on tin; motor, therefore with 2. week current. Point A shows the small initial resistance which the varinlion-resistance would slimy in a cold state. By the switching on l' at constant additional resistance this initial value is increased to the point or u, and hereby, as explained, the shock of the (HP rent is conshlei-al'ily reduced.

The dilferent strengths of the current are easily found by dividing" the amounts of the absorbed tensions and the resistances. The periodv of the heating oi the vnriators n'utrked with 71,, b and it, v, the period ot' the cooling with'b, 1 and so on, the renewed reheating of the rest of the vzu'ialoi's is shown by'd c, and .2 'u and the renewed cooling by e f and u, w the short-circuitings are shown by a, (Z, and f, ,7, respectively w, a and so on.

he above described apparatus show the W0 'l the Variation-resistances uncle? ting UL s ep ditierent loads, during the different of switching, with itii'erent amounts heat-capacity and i rtie of the variutoi's, with and without any addition of a constant resistance, and these props ties the variations of the amounts of the resistances of conductors with high tcinperetnre c ii cients, especially of iron, make it Pboqlblfi to Work with one, or several 3' W tt-h m oft for the tliti'erent either with the hand 0 DUI ore, a d c cnrrent or in in claim as my inve" site to secure by United States Letters fatin a device the class describ d. n motor circni, a. self regulating resin consisting of :1 pltrality of resistance inc-ins h: ting; -.1 high positive t inperuti i 1 -e coetiicien'l; connected. in series nnrellel arranged t" be included in the motor cunt, a substantially constant: resistance c nected with the resistances a solenoid, a contact nicmlnn, connecti the luilei' with the between illlfl," resistan e and also wit the Jolene-ill, a contact in net-led with the positive lead of the circuit, on ei'nuiturc adjacent to the solenoid, connected .nitl: the positive lead and ill of the brushes end the :onncctcd naent of the core oi the solenoid, coin doctor connecting the core of the solenoid with ccrtuin oi' the resistances for short vizcuiling u poi-lion oi the latte and means For comic-cling;ihc solenoid Willi the negolive lcml oi' the circuit.

53. ft doviceolthe chui'ac er (lest-timid. coinpi'isiug n constant resistance and :a plurality of groups oi sel'i iwygulalinn resistanc s tornml with i-oniluctm's oi high tempo lure coellic his, suiil conslunl resistance, nil oi said groups and an ai'nunure cmnnrclotl in series.

3.1%. sterling i'csistnnce totelmrtrooi'iotors comprising a substuuliully constant resistance and e l n'ulily ol thin iron i'vsishancesr-onnccted iii-parallel with each other, said comtnnt resistance and sold iron rosistunces being connected lIl-eLllQH with each other and with the Hilllillill'l! of said motor.

5;. ln :1 motor starter, a group of resistant-cs co-ingnising: independent sections, each .compi-isintg' a coil, ill electro-uiugnetic ilevice [or cutting out. one of the sci-lions, said l i. to connect the oonim'i members upon inotc stituting units of a predetermined value, the units ot the respective sections being connected in series, an

electromagnetic (levlce for cutting out one of the sections, said constant resistance connectedl device being automatically operated by an increasc of voltage, the resistance of the remaining section increasing at the moment of cutting out in a degree and for substantially corresponding with the ini crease of voltage resulting from such O]')("1' "tion and a constant resistance connected with the group of resistances first incutionecl.

In testimony whereof I allix my signature in presence of two witnesses.

i Manna KALLMANN. i 'J I Witnesses HENRY Hixsrnn, VVoLnmmn HAUPT.

a periorl 

